Two years after a Merlin HC Mk 4 flying from HMS Queen Elizabeth ditched in the sea off Dorset, killing Lt Rhodri Leyshon, the board of enquiry report has finally been published. The inquiry found that a fractured engine component triggered an emergency that the crew misdiagnosed, after which two serviceable engines were shut down, leaving the helicopter without power at low level over the sea at night. The report revealed that a component failure, ambiguous cockpit warnings, and crew misdiagnosis led to the fatal ditching.
During a night deck-landing exercise from HMS Queen Elizabeth, a split fuel pump diaphragm on engine two caused a sudden power surge. The aircraft's management system automatically throttled back engines one and three to compensate. Due to ambiguous cockpit warning logic, the crew misdiagnosed this as a double-engine failure and manually shut down the two functional engines. Engine two then tripped its overspeed protection, leaving the helicopter without power.
The investigation cited several compounding factors, including component testing procedures by engine maker Safran, reduced crew flight currency, a breakdown in crew resource management and equipment issues during the post-crash rescue.
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